均质砂土地基基坑渗透破坏模型试验研究

Influence of shield tunneling on displacement of adjacent buildings

采用自制基坑渗流模型箱及配套试验装置,观测土体破坏及水头变化情况,研究承压水头变化与土体渗透破坏关系,揭示砂土地基基坑渗透破坏机理,试验通过改变防渗墙的入土埋深,观察土体发生渗透破坏的临界水头差。结合PLAXIS有限元数值模拟软件,对基坑的渗流场进行分析。研究结果表明:均质砂土地基渗透破坏形式为楔形破坏;渗流过程中,水在土体中有明显绕过防渗墙的流向,从而增加了渗流路径,减小了水力梯度;防渗墙嵌入深度增加同一深度,其防渗效果不同。

The self-made foundation pit seepage model box and supporting test device were used to observe the soil damage and head change,study the relationship between the change of the confined head and the soil seepage damage,and reveal the mechanism of the seepage failure of the foundation pit of the sand foundation.The depth of the soil is buried,and the critical head difference of the soil infiltration failure is observed.Combined with the PLAXIS finite element numerical simulation software,the seepage field of the foundation pit is analyzed.The results show that the osmotic failure mode of homogeneous sand soil foundation is wedge-shaped failure;in the process of seepage,the water in the soil obviously bypasses the flow direction of the anti-seepage wall,thereby increasing the seepage path and reducing the hydraulic gradient;the seepage prevention wall for each increase of the depth of embedding,the anti-seepage effect changes are inconsistent.